1. Field of the Invention
The present invention relates to a display apparatus that produces a display by applying a voltage to an electro-optical conversion material and, more particularly, to a display apparatus having display areas of different resolutions, wherein the electro-optical conversion material is a liquid crystal material.
2. Description of the Related Art
In the fields of various measuring instruments, electronic shelf labeling systems, etc., it is practiced to produce a display of ordinary characters, graphics, or the like, which does not require a particularly high resolution, and a display of bar code or the like, which requires a high resolution, simultaneously on a single display panel.
Patent Document 1 (Japanese Examined Patent Publication No. H07-65909) discloses a technique for displaying a character screen, on which numerical values measured by a measuring instrument or various kinds of information are displayed in numbers or letters, and a bar code screen, on which the numerical values measured or the various kinds of information are displayed in bar code, simultaneously on a single display panel. However, with the technique disclosed in Patent Document 1, as the character screen and the bar code screen are displayed at the same resolution, the resolution of the display panel has had to be made to match the resolution required of the bar code display; that is, even when a low resolution suffices for the display of the character screen, the entire display panel has had to be designed to provide the high resolution required of the bar code display, resulting in the problem that the display panel requires the use of higher performance driving circuits, etc. and the cost increases unnecessarily.
A technique that addresses the above problem is disclosed in Patent Document 2 (Japanese Unexamined Patent Publication No. 2003-222893). The technique disclosed in Patent Document 2 concerns an electronic shelf labeling system that displays a matrix display section, in which ordinary characters are displayed, and a bar code display section, in which bar code is displayed by static driving, simultaneously on a single panel but at different resolutions. This display panel has a dot display section comprising column electrodes and row electrodes arranged in a matrix pattern, and a rectangular-segment display section comprising one common electrode and segment display electrodes disposed opposite the common electrode and electrically connected to the column electrodes in a one-to-one corresponding relationship. As the rectangular-segment display section is driven by the static driving method, the display panel as a whole is constructed using a liquid crystal material having a memory operation mode.
According to the technique disclosed in Patent Document 2, the dot display section for displaying ordinary character information is driven in time division fashion by using the column electrodes and row electrodes, while the segment display section for displaying bar code is driven by static driving (non-time-division driving) by using the one common electrode and the segment display electrodes disposed opposite to it. In this technique, a signal is input to each segment display electrode via its corresponding column electrode by electrically connecting the segment display electrode to the column electrode. This leaves no choice but to make the segment display electrodes correspond one for one with the column electrodes, leading to the problem that the number of segment display electrodes cannot be made larger than the number of column electrodes. There has also been the problem that, when the resolution of the segment display section is made higher than the resolution of the dot display section, a non-display area having no display pixels occurs in the segment display section and it is not possible to use that area for display. An object of the present invention is to solve these problems associated with Patent Document 2.